Image sensors are widely used in digital cameras, cellular phones, security cameras, as well as, medical, automobile, and other applications. One type of image sensor is known as a complementary metal-oxide-semiconductor (CMOS) image sensor. Multiple CMOS image sensors are typically formed on a semiconductor wafer that is then separated into several dies, each die including at least one image sensor. The semiconductor die is then assembled into a semiconductor package. The semiconductor package provides protection and includes pins, leads, or other chip-scale interfaces, which are then used to connect with circuits that are external to the package. The semiconductor die may be formed having a plurality of bonding pads on the surface of the die for internally connecting (e.g., wire bonding) the image sensor to the pins of the semiconductor package.
The technology used to manufacture image sensors, and in particular, CMOS image sensors, has continued to advance at great pace. For example, the demands of higher resolution and lower power consumption have encouraged the further miniaturization and integration of these image sensors. One field of application in which size and image quality is particularly important is medical applications (e.g., endoscopes). For medical applications the semiconductor package must typically be very small. For example, the need for the endoscopes to be smaller so as to access various small spaces inside the body may be limited by the size of the image sensors mounted on the endoscopes. This is due to the size and pitch requirements of the bonding pads which limit the overall size of the image sensors. The relative percentage of the die area taken up by bonding pads increases as the size of the typical image sensor decreases. Therefore, as the image sensors decrease in size, it becomes ever more difficult to accommodate the number of bonding pads typically included on the semiconductor die.